Gotta love the internet...OP asks for info on Gun #1 and gets replies about Gun #2, Gun #3 and Gun #4...
I bought a MAX-9 and have put about 250 rounds through it without any of the malfunctions others have reported. Perhaps it's a matter of time, or maybe I have a unit that was made after all the early users identified the bugs and subsequent fixes.
I found it to me a great replacement for my Kahr MK9, as it's significantly lighter, even though it holds almost twice the rounds.
I did do one thing however, I changed the trigger to the Galloway Precision Maxxis Short-Stroke Trigger. Being used to the long, steady trigger pull of the Kahr, I thought I'd be OK with the MAX-9's long pull. It ended up feeling a bit strange to me, so I changed the trigger to the Maxxis **
I think a lot of criticisms of the MAX-9 are a bit nitpicky..."feels cheap", "rattles", takedown pin design should be different, etc. It's a tool for use, not a museum piece or a collector piece. It's a workhorse in the Ruger style, not necessarily a beauty, but it'll do the job. I think the detractors are expecting a bit much in some cases (not those that have experienced function issues, that's different).
As others have mentioned, I'd suggest trying one out if you have an opportunity, because no matter what our advice is, any gun needs to fit you and satisfy you...no one else.
Aqualung
** Let's not derail the thread with all the inevitable Ayoobisms that a carry gun must nevereverevereverever be modified...